NEW PHOTOS: Explosions and Sports Cars on Transformers Set

The trailer opens with astronauts discovering a Cybertonian spacecraft hidden on the Moon's surface. The Autobots learn of it and must beat the Decepticons to reach the craft first and move a head in the Transformers' final war.

This third epic battle puts the city of Chicago under siege, taking down the city's major land marks and tearing up most of downtown.

During filming in Chicago, film director Michael Bay said the Chicago Film Office allowed him to do things in the Windy City that other cities wouldn't have permitted. He lauded the city's people and its architecture.